This invention relates in general to child safety seats for use in passenger vehicles, and in particular to a restraint attachment assembly for use in securing a child safety seat to a passenger seat.
Automotive child safety seats have typically been secured to passenger seats of a vehicle using straps, such as the existing seat belt for adult passengers. The ends of the seat belt are anchored to structural members of the automobile. The seat belt is directed through apertures or slots formed in the child safety seat, thereby securing the child seat relative to the seat belt. It is often laborious and sometimes complicated to fasten the child safety seat by means of the seat belt. Due to the flexible nature of the seat belt, the position of the child seat may also shift during operation of the vehicle.
To overcome these problems associated with securing a child safety seat with the existing seat belt, various regulations have been implemented requiring standardized structures and methods for securing child seats within an automobile. One such regulation was promulgated by the U.S. National Highway Traffic Safety Administration, entitled "Federal Motor Vehicle Safety Standards; Child Restraint Systems; Child Restraint Anchorage Systems", (64 FR 10786). The regulation requires that motor vehicle manufacturers provide a new way of installing child seats that are standardized and independent of the vehicle seat belts by use of a new anchorage system. Suitable child safety seats will include restraints or latches for coupling to the anchorage systems.
There is illustrated in FIGS. 1 through 3 a child safety seat 10 coupled to a vehicle passenger seat 12 by means of a prior art attachment assembly, indicated generally at 14. The attachment assembly 14 is an example of an anchorage system corresponding to the above mentioned regulation. The attachment assembly 14 includes a pair of spaced apart brackets 16 which are fastened to a cross member 18. The cross member 18 extends laterally across the seat 12 and is secured relative to the vehicle seat 12 to provide a rigid support for transmitting the load or force from the child seat 10 upon impact or rapid deceleration of the vehicle, as described in detail below. The cross member 18 is formed from a hollow tube having a generally circular continuous cross-sectional shape.
The brackets 16 are identical in structure and function. The brackets 16 are formed from a rod having a continuous circular cross-sectional shape. As best shown in FIGS. 2 and 3, the brackets 16 are generally U-shaped having a pair of legs 20 extending from ends of a cross bar 22. The legs 20 are identical in shape and have elongated parallel straight portions 23 and end portions 24. The straight portions 23 extend in a rearward direction from the cross bar 22 and curve downward in an arcuate shape following an upper rear contour of the cross member 18 to form the end portions 24. The end portions 24 of the legs 20 partially wrap around an upper arcuate surface 26 of the cross member 18. The end portions 24 are welded to the cross member 18 along their entire arcuate length. The arcuate surface 26 extends longitudinally along the length of the cross member 18. All of the end portions 24 of the legs 20 of both pairs of brackets 16 are secured along the arcuate surface 26.
As shown in FIG. 1, the straight portions 23 and the cross bar 22 of the brackets 16 extend slightly outwardly or protrude from the intersection of a seat bottom 12a and seat back 12b of the seat 10. The cross bars 22 function as receiving portions for the coupling of a pair of corresponding latch mechanisms 30 secured to the child seat 10. The latch mechanisms 30 are located on opposed bottom side corners of the child seat 10.
The forces imparted from the child seat 10 upon rapid deceleration of the vehicle are transmitted through the latch mechanisms 30, the brackets 16, and the cross member 18. During a forward load, in which the child seat 10 is propelled in a forward direction, as indicated by an arrow 32 in FIGS. 1 and 2, all of the legs 20 are substantially in tension. Note that the straight portions 23 can be angled slightly upward, as shown in FIG. 1, or can be substantially horizontal, as shown in FIG. 3.
During a lateral load, in which the child seat 10 is propelled in either lateral direction of the vehicle, as indicated by an arrow 34 in FIG. 2 (perpendicular to the forward direction 32) a moment is created about the center of gravity of the child seat 10 such that one of the latch mechanisms 30 pulls on its corresponding bracket 16, while the other latch mechanisms 30 pushes against its corresponding bracket 16. This lateral load causes the straight portions of one of the brackets 16 to be in tension, and causes the straight portions 23 of the other bracket 16 to be in compression. The bracket 16 which is substantially in tension generally provides adequate force resistance and generally does not deflect by a substantial undesirable distance in the forward direction 32. However, for the bracket 16 which is substantially in compression, the elongated straight portions 23 will crumble or tend to fold on themselves under sufficient force, which can cause the latch mechanism 30 and child seat 10 to deflect a substantial undesirable distance in a rearward direction, opposite from the forward direction 32, and also in the lateral direction 34. During a lateral load, the forces will generally also impart a bending load at an intermediate portion 36 between the straight portions 23 and the end portions 24 of the legs 20 of the brackets 16. During a lateral load situation the end portions of the brackets 16 defined by the cross bar 22 can move a substantial undesirable distance in the lateral directions 34. Generally, the longer the straight portions 23 of the brackets 16 extend from the cross member 18, the larger the cross bars 22, and subsequently the child seat 10, will deflect.
Since the center of gravity of the child seat 10 is located above the attachment assembly 14, a lateral force imposed from the child seat 10 may impart an upward force on one of the brackets 16. During an upward load, in which the latch mechanism 30 is propelled in an upward direction, as indicated by an arrow 38 in FIGS. 1 and 3, the corresponding bracket 16 will bend in a similar manner as when subjected to a lateral load, i.e., a bending load is imparted at the intermediate portion 36 of the legs 30, which may also result in a substantial bending distance of the cross bar 22 of the bracket 16. Of course, the brackets 16 can be subjected to any combination of forward, lateral, upward, and downward forces.